Photographic film and process of producing same



United States Patent No Drawing. Filed Feb. 3, 1969, Ser. No. 6,367 2 Ciairns. (Cl. 252-495) This invention relates to photographic film. More particularly, this invention relates to a photographic film having good slippage properties, to a process of producing the same and to a composition which may be used in the process.

As is well known, the handling, winding and unwinding of photographic film presents numerous problems characteristic to this field. One of these problems is poor slippage of the-film which produces friction sufficiently great to cause jamming of the camera or magazine and even breakage of the film. This problem is especially vexing in the case of cine and 35 mm. film. Friction on the film also generates static with a consequent damage to the light-sensitive coating of the film.

There have appeared suggestions in the prior art for treating photographic film to improve the slippage characteristics thereof. One such technique proposes the use of antifriction substances incorporated in the film. However, the materials employed up to the present time have not proved entirely satisfactory for various reasons. Thus, some of these materials do not adhere to the nonporous base of the film sufficiently well to withstand the hard usage to which the film is subjected. In some cases, the materials adversely efiect the sensitivity of the lightsensitive layers of the film while still others cannot withstand the treating baths to which photographic film is usually subjected.

It is accordingly an object of this invention to provide a novel composition suitable for use as a slippage agent for photographic film.

It is a further object of this invention to provide a photographic film having a layer thereon of a composition capable of increasing the slippage characteristics of the film which layer does not adversely effect the lightsensitivity of the light-sensitive layer, is capable of withstanding the treating baths to which the film is subjected and tenaciously adheres to the film base.

It is a still further object of this invention to provide photographic film having a layer thereon comprising a mixture of an a kyl silicone and an aryl silicone to increase the slippage characteristics of the film.

A still further object of this invention is to provide a process of treating a photographic film to increase the slippage characteristics thereof by treating the film with a backwash solution containing a mixture of an alkyl silicone and an aryl silicone.

Other objects and advantages of this invention will appear to those skilled in the art from the detailed deseription thereof given below.

The objects of our invention are attained by incorporating a mixture of an alkyl silicone such as methyl silicone and an aryl silicone such as phenyl silicone in a backwash solution which is then applied to the film base.

The alkyl silicones, such as the methyl silicones, have been found to be excellent slippage agents for photographic film when applied to the base opposite the emulsion during film processing. However, when it is desired to incorporate an alkyl silicone into a backwash solution for the application to the film base, difficulties are encountered. These difficulties are due to the fact that the highly polymerized alkyl silicones having high viscosities are insoluble in the solvents used in the back wash solution. The typical solvents comprise mixtures of alcohols and ketones as for example methanol-acetone, acetone-dichloroethane, methanol-methyl acetate etc. We attempted to emulsify the alkyl silicones with the alcoholketone solvent, but these emulsions proved unstable with concomitant breakup and precipitation of the silicone. Although partially polymerized alkyl silicones having lower viscosities are soluble in the alcohol-ketone solvents, they are not compatible with cellulosic film base and cause blush and hazy coatings.

We have now found that excellent coatings possessing the desired slippage properties are produced if mixtures of an alkyl silicone such as methyl silicone and an aryl silicone such as phenyl silicone, for example, are used to form the coatings. The alkyl silicones used should have a viscosity of less than 50 centipoises. The amount of silicones present in the solution are preferably from .05 to 5% by weight of the alkyl silicone and from .2 to 5% by weight of the aryl silcone. The preparation and properties of the silicones as used herein are well known and described in the chemical literature and in this connection, reference is made to Rubin Gutoffs article entitled The Silicone Fluid Manufacture, published in Industrial And Engineering Chemistry, vol. 49, pp. 1807 .to 1811.

We have found, as a suitable aryl silicone polymer for practicing the invention, a phenyl silicone polymer purchased from the Dow-Corning Company as DC-SSS. As a source of an alkyl silicone polymer, we use a methyl silicone polymer obtained as DC200 from the Dow-Corning Company.

Any known solvent or solvent mixture used in forming a subbing or a backwash solution may be used according to our invention. The solvent mixtures described previousiy are satisfactory. Others are known in the art. We prefer to use a composition containing 70% acetone and 30% methanol.

Any typical film base may be coated with the novel solution. Examples of such bases are the cellulose esters such as cellulose acetate, cellulose nitrate, cellulose acetate butyrate, etc., the vinyl resins such as vinyl acetate and many others.

The following specific example of our invention is given. It is to be understood, however, that this example is given by way of illustration and not by way of lirm'tation.

Example A backwash solution containing 70% acetone and 30% methanol as the solvent was divided into five parts and the following different additives were incorporated in these parts:

A-Typical slippage additive of prior art.

B2% phenyl silicone polymer (Dow Corning DC5S5).

C--2% phenyl silicone polymer (DC-555)+1% methyl silicone polymer (5 cs.) (Dow Corning DC-ZOO).

D2% methyl silicone polymer (5 cs.) (Dow Corning DC-ZOO).

(All percentages of B, C and D are by weight.) E-No additive.

All of the solutions appeared clear and. free from any precipitation. These separate solutions were coated on separate samples of film as the backwash. These film samples were also subbed in the conventional manner on the side opposite the side to which the backwash was applied. The quality of the coatings of the various samples was observed and the samples were then tested for slippage. The test consisted of dragging a 500 gram weight across the face of the film sample treated with the backwash solution with a spring balance and obtaining the reading on the balance. The results obtained appear in the table below.

It will be observed from the table (small numbers desirable) that the slippage agent of sample (C), comprising a mixture of phenyl silicone polymer and methyl silicone polymer, possesses far superior slippage properties compared to phenyl silicone alone or the prior art slippage agent. The coating quality of the mixture of silicones was satisfactory whereas the coating quality of the methyl silicone alone was unsatisfactory, being very hazy.

Our invention is not limited to the detailed description thereof contained herein, but includes all modifications that fall within the scope of the appended claims.

We claim:

1. A backwash solution for increasing the slippage properties of photographic film base consisting essentially of a mixture of a dimethyl polysiloxane having a viscosity ranging from 100 and 1000 centistokes at 25 C. and a phenylmethyl polysiloxane having a viscosity ranging from 10 to 30 centistokes at 25 C., and a mutual solvent medium for said polysiloxanes consisting essentially of a mixture of acetone and methanol, the amount of polysiloxane being from 0.05 to by weight of the 4 solvent in the case of the dimethyl polysiloxane and from 0.2 to 5% by Weight of the solvent in the case of the phenylmethyl polysiloxane.

2. A process of enhancing the slippage properties of a photographic film base which comprises forming a backwash solution by dissolving a mixture consisting essentially of dimethyl polysiloxane having at 25 C. a viscosity ranging from 100 to 1000 and a phenylmethyl polysiloxane having at 25 C. a viscosity ranging from 10 to 30 centistokes in a mutual solvent medium for said polysiloxanes consisting essentially of a mixture of acetone and methanol, the amount of polysiloxanes being from 0.05 to 5% by weight of the solvent in the case of the dimethyl polysiloxane silicone and from 0.2 to 5% by weight of the solvent in the case of the phenylrnethyl polysiloxane, and contacting, the base of the photographic film with the said solution.

, References Cited in thefile of this patent UNITED STATES PATENTS 2,441,423 Elliott et al. May 11, 1948 2,443,353 Hyde et a1. .1. June 15, 1948 2,566,364 Pedlow et a1. .0, Sept. 4, 1951 2,749,253 Shoemaker etal. June 5, 1956 2,875,098 Blatz Feb. 24, 1959 Dickard May 23, 1961 OTHER REFERENCES International Projectionist, May 1959, page :10.

, McGregor: Silicones and Their Uses, page 11, McGraw- Hill, New York'(1954). 

1. A BACKWASH SOLUTION FOR INCREASING THE SLIPPAGE PROPERTIES OF PHOTOGRAPHIC FILM BASE CONSISTING ESSENTIALLY OF A MIXTURE OF A DIMETHYL POLYSILOXANE HAVING A VISCOSITY RANGING FROM 100 TO 1000 CENTISTOKES AT 25* C. AND A PHENYLMETHYL POLSILOXANE HAVING A VISCOSITY RANGING FROM 10 TO 30 CENTISTOKES AT 25* C., AND A MUTUAL SOLVENT MEDIUM FOR SAID POLYSILOXANES CONSISTING ESSENTIALLY OF A MIXTURE OF ACETONE AND METHANOL, THE AMOUNT OF POLYSILOXANE BEING FROM 0.05 TO 5% BY WEIGHT OF THE SOLVENT IN THE CASE OF THE DIMETHYL POLYSILOXANE AND FROM 0.2 TO 5% BY WEIGHT OF THE SOLVENT IN THE CASE OF THE PHENYLMETHYL POLYSILOXANE. 